Front wheel lean mechanism



Sept. 1, 1959 c. P. LELITER FRONT WHEEL LEAN MECHANISM Filed Feb. 12, 1957 If A l QMmM /hvn XWQM Lax/Wa t Mrlmg Patented: Sept. 1,. 1959.

2,902,100 FRONT WHEEL LEAN MECHANISM- Chester P. Leliter, Springfield, 111.; assignor to, Allis- Chalmers Manufacturing Company, Milwaukee, .Wis.

Application Febriiary 12, 1957, set-aim. 639,523 6 Claims. c-1. 180-1 The present invention relates to' a self-propelled earth working'vehicle of'the type having mechanically'operated mechanisms and it is more particularly concerned with an improved front wheellean mechanism.

Heretofore' various types of' mechanically operated wheel lean mechanisms have been proposed to prevent side slipping which is a characteristic inherent in all conventional type motor graders while the blade-is positioned at an angle and in contact with the ground or material being worked. Such mechanisms, I however, have not proved entirely satisfactory for anumber of reasons. For example, all of the conventional front wheel lean mechanisms incorporate some type of stop device to limit the amount of tilting of the wheels in each direction. Therefore, the power control box must be forwardly engaged to supply torque which will cause tilting of the wheels in one direction and in order to return the wheels to their upright position or to effect tilting in the opposite direction, the control box must be reversed. Serious difliculty has been experienced in operating such wheel lean mechanisms since oftentimes it is impossible for the operator to determine the precise instant when the wheel lean mechanism reaches the stop. Consequently, when the stop is reached and the power control box is not promptly disengaged, torque will continue to be supplied to a locked system causing serious damage to either the lean mechanism, the gearing within the power control box itself or to the shafting which interconnects the wheel lean mechanism with the control box. Prior to the applicants invention, no satisfactory solution to this problem had been offered.

It is, therefore, an object of the present invention to provide a new and improved front wheel lean mechanism which will overcome the disadvantages heretofore described.

It is a further object of the present invention to provide an improved front wheel lean mechanism wherein no stop device is required and thefront wheels are tiltable in either direction regardless of the direction of the torque being supplied.

It is a further object of the present invention to provide an improved front wheel lean mechanism wherein an eccentric member capable of 360 degrees unrestricted rotation is operable to tilt the front wheels in either direction although torque is being supplied in one direction only.

It is a further object of the invention to provide a Fig. 1 shows a front view of a self-propelled motor grader with the front wheels being tilted to the left;

Fig. 2 shows a top view of the front wheel lean-mach a-nism; and v v Fig. 3 shows a diagrammaticview of a mechanically operated front'wheel lean mechanism including the power p y- Referring to Figs. 1 and 3, the motor grader 4-is of the conventional type having a main frame 6 on which is carried mechanically operated mechanisms suchas the circle lift 7 and the front wheel lean mechanism 8 (best shown in Fig. 3). Thevarious mechanisms are selectively operated by corresponding. hand levers 9 of the power control box 11-. Traction wheels'12 are located at: the rear of the vehicle onopposite'lateral sides respectively of main frame 6. A ground engaging blade 13-is attached to the. circle member 14. A double frame frontv axle' assembly or support 16' is mounted at: the forward part: of the main frame 6 for pivotal'movement about the hon'zontal axis of pin 17. A wheel supporting means 18 and 19 include: knuckle members 20 andt 21 mounted respectively on opposite ends of the axle assembly 16 for tilting movement respectively about the axis of pins 22 and 23 which are received in transverse boreswhich are provided in axle 16; spindles 24 and 26 which are journaled. respectively inthe knuckle members 20 and 21 for movement about their own axis which is substantially vertical when the knuckles are not in a tilted position; and stub shafts 27' and 28- being normal to and rigidly mounted respectively on spindles 24 and 26. Front wheels 31 and 32 are carried respectively on stub shafts 27 and 28 for rotation about the axis thereof. The wheel supporting means 18 and 19 are operative to permit steering of the front. wheels 31 and 32 about the axis of the spindles 24" and 26 and tilting or leaning of the wheels 31'- and 32' about the longitudinally" extending horizontal axis of pins 22 and 23.

Engine 34, power take-off 33, shafts 36, 37, 38, 39 and 41 and power control box 11 (best shown in Fig. 3); constitute a conventional typeof power means: for selectively supplying torque to a worm gear mechanism 35'. Hand lever 9 has three positions being biased to neutral from either a forward or rearward shifted position. The orientation being such that forward shifting of the hand lever 9 indicates movement toward the front of motor grader 4 while rearward shifting indicates movement toward the rear of the vehicle (as viewed in Fig. 1), and the neutral position is the upright or vertical position of lever 9 shown best in Fig. 3. When lever 9 is shifted forward, gearing (not shown) in the power control box 11 is engaged thereby imparting torque which tends to rotate output shaft 38 in a clockwise direction, and when lever 9 is shifted rearward, reverse gearing (not shown) is engaged thereby imparting a torque which tends to rotate output shaft 38 in a counterclockwise direction and while lever 9 remains upright or in neutral, no torque whatsoever is imparted to shaft 38.

Referring to Fig. 3, the front wheel lean mechanism 8 operates in the following manner. A conventional type power take-01f 33 is attached in driven relation to the engine 34 which is mounted on the main frame 6 at the rear of motor grader 4. Torque is transmitted from power take-off 33 through a first universally jointed shafting 36 to the input shaft 37 of a conventional type mechanically operated power control box 11. Upon selective shifting of lever 9 torque is next transmitted to output shaft 38 and thence through a second universally jointed shafting 39 to an operating shaft 41 which carries a first sprocket 42 at one end thereof. Torque is then supplied to the worm gear mechanism 35 from sprocket 42 to a second sprocket 43, which is keyed on worm shaft 46, and which is connected by drive chain 44 to sprocket 42. The worm gear mechanism 35 includes worm shaft 46, a worm 51 fixedly carried on shaft 46 (as by keying), a worm wheel 49 being in constant mesh with worm 51, and a crank shaft 48 on which is fixedly carried as by keying a worm Wheel 49. \Vorm gear mechanism 35 acts as a torque transmitting means for supplying torque to an operating crank 47 which is splined on one end of crank shaft 48. Operating crank 47 includes a crank pin 52 which is rigidly attached thereto. A linkage means, including a first link arm 53 and a second link arm 54, respectively, interconnects the wheel supporting means 18 and 19 and the operating crank 47. Arm 53 is connected at one end by pin 56 to bracket 57 which is integral with knuckle member 20 and the other end is pivotally mounted on crank pin 52. Arm 54 is pivotally connected at one end by pin 58 to bracket 59 which is integral with knuckle member 21, and the other end is pivotally mounted on crank pin 52 adjacent to the end of arm 53.

Referring to Fig. 2, the worm shaft 46 and the crank shaft 48 are respectively journaled in housing 61 which in turn is fixedly attached by bolts 62 to brackets 63 and 64, which are in turn secured to the axle assembly 16 as by welding.

Reference is again directed to Figs. 1 and 3. The orientation of the wheel lean mechanism 8 and front wheels 31 and 32 is as viewed in Fig. 1 which shows the motor grader 4 as seen from the front. The upright position of the operating crank 47 (best shown in Fig. 3) is taken as the reference point of zero degrees rotation at which point the front wheels are also in an upright position. By shiftin lever 9 rearward, operating crank 47 is caused to be rotated counterclockwise, from the reference point and arms 53 and 54 are respectively displaced longitudinally to the left, thereby causing the knuckle members 20 and 21 to be tilted to the left about the horizontal axis of pins 22 and 2.3 respectively. As operating crank 47 reaches approximately 90 degrees of rotation (as shown in Fig. 1), arms 53 and 54 have reached their furthest longitudinal displacement to the left and knuckle members 20 and 21 have reached their maximum degree of tilting to the left and wheels 31 and 32 their greatest angle of lean. The exact point of maximum lean occurs when pins 52, 56 and 58 are brought into alignment on the same axis. From this position the hand lever 9 can be shifted either forward or rearward to cause clockwise or counterclockwise rotation since in either instance operating crank 47 will displace arms 53 and 54 to the right and knuckle members 20 and 21 will thereby return the wheels 31 and 32 to their upright position at a point of either Zero or 180 degrees of rotation. Should operating crank 47 be rotated from either zero degrees in a clockwise direction or from 180 degrees in a counterclockwise direction, arms 53 and 54 will be displaced to the right, simultaneously tilting knuckle members 23 and 21 to the right thereby leaning the Wheels 31 and 32 to the right also. The furthest longitudinal displacement of arms 53 and 54 to the right and hence the maximum degree of tilt to the right of the knuckle members 20 and 21 is achieved when operating crank 47 reaches a point at approximately 270 degrees counterclockwise (or 90 degrees clockwise) rotation from the reference point. From this position the wheels 31 and 32 can be restored to their upright position by either a clockwise or counterclockwise rotation of operating crank 47 since in either instance the arms 53 and 54 will be displaced to the left until such time as the operating crank 47 returns to the reference point (which is also 360 degrees) or a point of 180 degrees rotation from the reference point. It is well known that worm gear mechanisms are self-locking except when the worm is rotated. This feature is employed here to maintain wheels 31 and 32 in their respective upright position or in any of their various adjusted lean positions While 4 the hand lever 9 is in neutral and no torque is bein supplied to the wheel lean mechanism 35 The crank shaft 48 operating crank 47 and crank pin 52 in effect form an eccentric member capable of 360 degrees of unrestricted rotation and which is operative to translate the circular motion of operating crank 47 and crank pin 52 into reciprocating motion to link arms 53 and 54 to cause tilting of the wheel supporting means 18 and 19 so as to lean wheels 31 and 32 in either direction, regardless of the direction of the torque being supplied to the worm gear mechanism 35. This feature permits the operator to very rapidly adjust the angle and direction of front wheel lean and to restore the wheels to an upright position from an adjusted lean position Without danger of damaging either the shafting 39 and 41, the power control box 11., or the worm gear mechanism 35.

It will be apparent from the drawings and the foregoing detailed description that a novel construction and design for a front wheel lean mechanism has been illustrated and described which Will overcome the disadvantages inherent in the conventional devices.

It should be understood that although the particular forms and details described herein illustrate only one embodiment of the invention, it is not intended to limit the patent granted hereon otherwise than is necessitated by the scope of the appended claims.

What is claimed is:

1. A wheel lean mechanism comprising a support, wheel supporting means mounted on said support for tiltable movement about a longitudinally extending horizontal axis, an eccentric member rotatable through 360 degrees of unrestricted rotation being mounted on said support, torque transmitting means carried on said support and coupled with said eccentric member to impart torque thereto, and linkage means connecting said eccentric member and said Wheel supporting means for transmitting reciprocating motion to the latter upon rotation of said eccentric member through 360 degrees.

2. A wheel lean mechanism comprising a support, wheel supporting means mounted on said support for tiltable movement about a longitudinally extending horizontal axis, a crank shaft rotatably mounted on said support, an operating crank fixed on said crank shaft, said operating crank being rotatable by said crank shaft through 360 degrees of unrestricted rotation, linkage means interconnecting said operating crank and said wheel supporting means for transmitting reciprocating motion to the latter upon rotation of said operating crank through 360 degrees of rotation and torque transmitting means carried on said support and coupled with said crank shaft to impart torque thereto.

3. A Wheel lean mechanism comprising an axle assembly having oppositely spaced ends, wheel sup-porting means mounted at said ends respectively for pivotal movement about a horizontal axis which is transverse to said axle assembly, a crank shaft journaled on said axle assembly, a worm wheel fixed on said crank shaft, an operating crank fixed on and rotatable by said crank shaft through 360 degrees of unrestricted rotation, linkage means interconnecting said operating crank and said Wheel suppporting means in motion transmitting relation to one another, a worm shaft journaled on said axle assembly, a worm fixed on said worm shaft being in constant mesh with said worm wheel, and means for rotating said worm shaft whereby said operating crank may be rotated through 360 degrees.

4. A wheel lean mechanism comprising an axle assembly having oppositely spaced ends, a housing fixedly secured to said axle assembly, wheel supporting means mounted at said ends respectively for pivotal movement about a horizontal axis Which is transverse to said axle, a crank shaft journaled in said housing, an operating crank being fixedly carried on and rotatable by said crank shaft through 360 degrees of unrestricted rotation in either direction, a link arm respectively interconnecting each of said wheel support means and said operating crank, a worm wheel fixed on said crank shaft, a worm shaft journaled in said housing, a worm fixedly carried on said worm shaft being in constant mesh with said worm wheel, and means for rotating said Worm shaft whereby said operating crank may be rotated through 360 degrees.

5. In a self-propelled earth working vehicle of the type having a main frame and mechanically operated mechanism, a front wheel lean mechanism comprising: an axle pivotally mounted on said main frame; Wheel support means mounted at opposite ends respectively of said axle for pivotal movement about a horizontal axis which is normal to said axle; a pair of wheels rotatably mounted respectively on said Wheel support means; a housing rigidly attached to said axle; a crank shaft journaled in said housing; a Worm Wheel keyed on said crank shaft; an operating crank splined on one end of and rotatable by said crank shaft through 360 degrees of unrestricted rotation in either direction; a first and second link arm, said first arm interconnecting one and said second arm the other of said wheel support means with said operating crank; a worm shaft journaled in said housing; a worm keyed on said worm shaft being in constant 6 mesh with said Worm wheel; and a power means on said main frame for selectively supplying torque to said worm shaft in either a forward or reverse direction to effect tilting of said front wheels in either of two directions regardless of the direction of said torque.

6. A wheel lean mechanism comprising a support, Wheel supporting means mounted on said support for tiltable movement about a longitudinally extending horizontal axis, an eccentric member rotatable through 360 of unrestricted rotation being mounted on said support, linkage means interconnecting said eccentric member and said wheel supporting means, said linkage means including a link pivotally connected to said eccentric member for transmitting reciprocating motion therefrom, to effect tilting of said Wheel supporting means, and torque transmitting means carried on said support and coupled with said eccentric member to impart torque thereto.

References Cited in the file of this patent UNITED STATES PATENTS 1,714,152 Wilson May 21, 1929 1,732,892 Hinds Oct. 22, 1929 1,875,778 Taylor Sept. 6, 1932 2,670,551 Keeler Mar. 2, 1954 

